Two component (epoxy/amine) structural foam-in-place material

ABSTRACT

The present invention relates to methods, materials, and products for forming a foamed product, comprising the steps of combining an epoxy-based component with an amine-based component. The epoxy component is cross-linked through a polymerization reaction catalyzed by the amine formulation. In this regard, a reactive mixture or exothermic reaction is created between the epoxy component and the amine component when combined. The heat generated by the exothermic reaction softens a thermoplastic shell of a blowing agent formulated within the epoxy component thereby enabling a solvent core within the thermoplastic shell of the blowing agent to expand from the heat generated by the exothermic reaction.

FIELD OF THE INVENTION

[0001] The present invention relates generally to foam-in-placestructural materials used for reinforcement of structural members. Moreparticularly, the present invention relates to a two-componentepoxy/amine foamed material exhibiting improved mechanical properties(good balance of high compressive strength, compressive modulus, glasstransition temperature and cured ductility) as well as enhancedshear-thinning characteristics.

BACKGROUND OF THE INVENTION

[0002] Traditional foam-in-place structural materials known in the artgenerally disclose polyurethane materials, polyurea, or epoxy-basedmaterials. These materials incorporate a method to create volumetricexpansion and a curing mechanism as well to effectuate curing at roomtemperature and achieve a degree of control of expansion and cure ratecharacteristics. Although these prior art materials are both useful andsuccessful in a number of applications, certain structural reinforcementapplications in the automotive industry, for example, would benefit froma material having an improved balance of mechanical properties, such asa higher compressive strength, little change in modulus over a broadtemperature range and a glass transition temperature that exceeds 200°F. In addition, improved cured ductility that enables the material todeform plastically when stresses exceeding the material yield strengthare applied would provide definite benefit. Further, these structuralreinforcement characteristics in many applications, includingautomotive, may also benefit from a shear-thinning structural materialwhich exhibits an increased viscosity at zero shear rate and a decreasedviscosity at higher shear rates prior to curing. This enables thematerial to flow more easily while being dispensed but then have flowminimally following dispensing. This shear thinning behavior can alsoassist with the development of a uniform, consistent foamed cellstructure by allowing more effective foaming gas entrapment.

[0003] As known by those skilled in the art, a number of factorsdetermine the suitability of a process for forming a foamed product ofthe type in which a blowing agent forms cells in a synthetic resin asthe resin is cured. Most significantly, the interaction of the rate ofcure and the rate at which the blowing gas is generated must be matchedto create the proper cured product. If the resin cures too rapidly thereis inadequate time for the gas to form the proper size and number of gasvoids in the finished product. Over expansion of the forming foamproduct must also be avoided. Rapid expansion due to a slow cure raterelative to gas evolution may cause the expanding foam to simplycollapse as a result of inadequate wall strength surrounding theindividual gas cells.

[0004] A number of prior art techniques are available to control therate of foam expansion and the cure rate. For example, a wide-range ofreactivities are available in commercial resins and curing agents. Inaddition, resins are available in a range of viscosities, which isanother parameter and can be used to control the foam expansion rate.That is, it is known that a low viscosity resin can generally beexpanded to a greater volume with a given volume of gas than a higherviscosity material; however, the resin must have sufficient viscosity tocontain the gas at the pressures at which it is generated in order forthe foam to be properly formed.

[0005] With respect to automotive applications, foamed products musthave good environmental resistance and, most significantly, in manyapplications they must protect metal from corrosion while maintainingadhesion to the substrate. In the past many foamed parts were made usingpolyurethane, which provides a number of desirable attributes. It isknown, however, that alternatives to urethane-based foams or moreprecisely materials based on the reaction of the isocyanate chemicalfunctional group are frequently more environmentally desirable, in partdue to the potential for unreacted functional groups in the finishedproducts and difficulty in handling isocyanate functional chemicals inmanufacturing processes. In addition, the polyurethane materials foundin the prior art fail to provide optimum mechanical properties,generally possessing lower elastic modulus strength and lower glasstransition temperature than what is capable with epoxy-based materials.In comparison with polyurethane materials, however, the epoxy-basedmaterials found in the prior art often exhibit both poor cured ductilityand higher viscosity during dispensing.

[0006] Accordingly, there is a need in industry and manufacturingoperations for a structural material, which exhibits improved mechanicalproperties, such as higher compressive strength, compressive modulus,and glass transition temperature, as well as better-cured ductility. Theimproved mechanical properties allow the structural material of thepresent invention to be capable of plastically deforming when loadedbeyond its yield stress. However, unlike prior art materials, there isno significant reduction in modulus or glass transition temperature. Inaddition, there is a need for an improved material, which can be used ina variety of applications wherein one or both components utilize athixotropic filler, which produces pronounced shear-thinningcharacteristics. By providing a material with excellent cured physicalproperties and desirable processing attributes, the present inventionaddresses and overcomes the shortcomings found in the prior art.

SUMMARY OF THE INVENTION

[0007] The present invention relates to methods, materials, and productsfor foam-in-place structural reinforcement of hollow structures such asautomobile cavities. In one embodiment, the present invention comprisesa two-component foam-in-place structural material for producing a foamedproduct. Though other resin systems are possible, the first component ofthe system includes an epoxy-based resin. Preferably, the firstcomponent is formulated with a physical blowing agent, and morepreferably one having a shell or skin that will change state to providevolumetric increase to create expansion. For example, the shell is athermoplastic that, upon heating, will melt or soften to enable asolvent core to expand the shell. The second component includes anamine, and is formulated with an agent for allowing the resultingmaterial to exhibit ductility with little reduction in modulus, glasstransition temperature, or both. It is contemplated that the amine ofthe present invention could be a primary or secondary amine. Generallyspeaking, the amine is an epoxy curing agent or modifier, andpreferably, a high solids epoxy curing agent, though it could be awater-borne epoxy-curing agent. Other examples of an amine suitable foruse in the present invention include polyamides, aliphatic amines, andcycloaliphatic amines as well as other agents that can function asaccelerators or catalysts. An optional thixotropic filler is included ineither or both of the first or second components, and possibly as astand-alone component. In one embodiment, this additive preferablycauses the material to have high viscosity at a near zero shear rate andlow viscosity at a higher shear rate, which is more commonly known inthe art as shear-thinning.

[0008] The present invention provides a method of forming a foamedproduct, which comprises the steps of combining the first component(with a blowing agent) with the second component (with a curing agent).The first component, preferably an epoxy, is cross-linked through apolymerization reaction with the second component of the formulation(e.g. an amine). In this regard, an exothermic reaction or reactivemixture is created between the-epoxy component and the amine componentwhen combined. The heat generated by the exothermic reaction softens thethermoplastic shell of the blowing agent formulated within the epoxycomponent thereby enables the solvent core within the thermoplasticshell to expand the thermoplastic shell and thereby create expansion. Ina preferred embodiment the mixture of materials is in liquid form.However, it is contemplated that the mixture of materials could alsocomprise a paste or solids of varying viscosities and textures.

DETAILED DESCRIPTION OF THE INVENTION

[0009] As used herein, all concentrations shall be expressed aspercentages by weight unless otherwise specified.

[0010] The present invention relates generally to a two componentstructural foam-in-place material and method for making the same formedby cross-linking reactions between an epoxy resin and a curing agentthat creates a three-dimensional covalent bond network. It iscontemplated that the addition of a curing agent to the epoxy resincauses the resin to cure or harden into a rigidified cross-linkedpolymer. When an epoxy resin is mixed with a curing agent containinglabile hydrogen atoms, the epoxy ring opens and reacts with thecurative. Generally speaking, cured epoxy foams are produced using oneof three types of curing agents, such as amines, polyphenols, andanhydrides. Cure of the foam is achieved by polyaddition whereby thecure reaction between the epoxy resin and a curing agent is typicallyexothermic and can generate a considerable amount of heat. The controlof such heat and the exothermic reaction is an important considerationof the foam-in-place material of the present invention. Since thefoam-in-place material of the present invention is particularly usefulin the production of automobiles and other vehicles to maintain and/orincrease the strength of structural members such as frame members,rails, rockers, pillars, radiator support beams, doors, hatches,reinforcing beams and the like, exothermic control prevents the charringor burning of the interior of the foam.

[0011] More particularly, the method and composition of the presentinvention has two main components: (1) an epoxy resin componentformulated with a physical blowing agent having a thermoplastic shellwith a solvent core, and (2) an amine curing agent component which, whencured, produces a material capable of plastically deforming whenmechanically loaded with an insignificant reduction in modulus or glasstransition temperature reduction when compared with traditionalepoxy/amine systems. In addition, a thixotropic additive is formulatedinto one or both the first and second components, which producesshear-thinning characteristics useful for processing and generation of afoamed product. Moreover, the exothermic reaction generated by thecombination or mixture of the first and second components serves tosoften the physical blowing agent, which consists of a thermoplasticshell with a solvent core. As the thermoplastic shell softens, thesolvent expands the shell to create an expanded particle. The preferredsolvent and shell is selected for its expansion properties when exposedto the heat of the exothermic reaction, which occurs duringpolymerization. However, by using the preferred fillers, and lessreactive amine functional materials such as an amine sold under thecommercial name GVI 4040, excessive exotherm, which would otherwise beproduced by the curing reaction (and which could produce charring), isprevented.

[0012] In a particularly preferred embodiment, the components orformulation of the present invention include the following:

[0013] Resin Component

[0014] The first or resin component of the present invention is selectedfor its structurally adhering characteristics and for impartingrigidity. Suitable resins may include a cross-linkable polymer and, morepreferably an epoxy. The properties of advantageous epoxy resins aredescribed, for example, in the chapter entitled “Epoxy Resins” in theSecond Edition of the Encyclopedia of Polymer Science and Engineering,Volume 6, pp. 322-382 (1986). The preferred epoxy resin has a numberaverage molecular weight of from about 350 to about 600 and, on average,each molecule of epoxy has from about 1.8 to about 2.5 epoxidefunctional groups. The preferred epoxy resin has a viscosity of fromabout 5,000 to 100,000 cps (Brookfield viscosity) at 70° F. and aspecific gravity of from about 1.0 to about 1.4. As stated, thepreferred form of the resin is a liquid and may further comprise a highviscosity resin with relatively low reactivity. Exemplary epoxy resinswhich could be utilized in the present invention include polyglycidylethers obtained by reacting polyhydric phenols such as bisphenol A,bisphenol F, bisphenol AD, catechol, resorcinol, or polyhydric alcoholssuch as glycerin and polyethylene glycol with haloepoxides such asepichlorohydrin; glycidylether esters obtained by reactinghydroxycarboxylic acids such as p-hydroxybenzoic acid or beta-hydroxynaphthoic acid with epichlorohydrin or the like; polyglycidyl estersobtained by reacting polycarboxylic acids such as phthalic acid,tetrahydrophthalic acid or terephthalic acid with epichlorohydrin or thelike; epoxidated phenolic-novolac resins (sometimes also referred to aspolyglycidyl ethers of phenolic novolac compounds); epoxidatedpolyolefins; glycidylated aminoalcohol compounds and aminophenolcompounds, hydantoin diepoxides and urethane-modified epoxy resins.Mixtures of epoxy resins may also be used in the present invention. Forexample, mixtures of liquid (at room temperature), semi-solid, and/orsolid epoxy resins can be employed. A preferable epoxy resin for use inthe present invention includes DER 331. As stated, the preferred form ofthe resin is a liquid. Other commercially available epoxy resins, whichmay be suitable in the present invention include, but are not limited toDER 317, DER 337 and DER 324. A resin forms from about 35% to about 99%by weight of the first or resin component and more preferably from about65% to about 98% by weight of the composition of the present invention.

[0015] It is contemplated that the resin component of the presentinvention may also be formulated with a blowing agent and, moreparticularly, a blowing agent having a thermoplastic shell with asolvent core. Because epoxies normally react with a curing agent withoutevolving volatiles, the addition of a blowing agent is typicallyrequired to create a foamed product. The blowing agent may be a chemicalagent, (i.e. one that thermally decomposes and evolves gas due to theheat of the exothermic epoxy reaction), or a physical agent, whichsimply vaporizes at its boiling temperature to liberate gas. In theevent that a chemical blowing agent is used, particle size of theblowing agent may be adjusted so as to provide the desired foamingcharacteristics in the cured foam. For example, smaller particle sizestend to provide foams having more uniform cell structure. In somealternative formulations of the present invention, it may be desirableto also use a blowing agent activator or accelerator so as to lower thetemperature at which release of gas from the blowing agent takes place.Suitable chemical blowing agent activators include, but are not limitedto, ureas (such as the surface-coated, oil-treated urea sold by UniroyalChemicals under the trademark BIKOT) polyols, organic acids, amines, andlead, zinc, tin, calcium and cadmium oxides and salts (includingcarboxylic acid salts).

[0016] Typically, from about 0.1% to about 2% of a blowing agent basedon the weight of the foamable composition is employed, although theoptimum amount will of course vary depending upon theactivator/accelerator selected, the amount of blowing agent, curetemperature and other variables. An example of a preferred physicalblowing agent, which according to the present invention is formulatedwith the first or resin component, is sold under the trade name Expancel820-DU. Most preferably, the solvent core of the blowing agent of thepresent invention is a liquid.

[0017] Amine Component.

[0018] The amine component of the present invention may be formulatedwith a curing agent, which enables the material to achieve modulus orglass transition temperature compared to materials found in the priorart but is still capable of significant plastic deformation followingcuring. In addition, the preferred amine component facilitates a curedstructural material having improved mechanical properties such as highercompressive strain to failure when compared with materials producedusing traditional curing agents. The presence of the enhanced mechanicalproperties is particularly useful in structural reinforcementapplications found in the automotive industry but whose utility is notlimited to such applications. Accordingly, the cross-linking of thefirst or resin component utilized in the present invention may beaccomplished by the addition of any of the chemical materials known inthe art for curing such resins. Such materials are referred to herein as“curing agents”, but also include the substances known to workers in thefield as curatives, hardeners, activators, catalysts or accelerators.While certain curing agents promote curing by catalytic action, othersparticipate directly in the reaction of the resin and are incorporatedinto the thermoset polymeric network formed by condensation,chain-extension and/or cross-linking of the synthetic resin. When thethermosettable synthetic resin is an epoxy resin, it may be particularlydesirable to employ at least one curing agent, which is anitrogen-containing compound. Such curatives (along with other curativesuseful for hardening epoxy resins) are described in the chapter in theEncyclopedia of Polymer Science and Engineering referenced above.Suitable compounds useful as curing agents include amines, aminocompounds, amine salts, and quaternary ammonium compounds. While anytype of amine could be used, it is contemplated that suitable aminecomponents for formulation in the present invention includecycloaliphatic amine curing agents which have a long cure time, relativeto other commercially available curing agents, with epoxy resins andserves to increase the glass transition temperature of the cured epoxy,thereby increasing mechanical stability at higher temperatures. Aparticularly preferred amine utilized in the present invention is soldby Air Products under the trade name Ancamine 2556.

[0019] Additive(s)

[0020] Further, the present invention comprises the formulation ofadditional additive component(s), which will cause either or both of thecomponents described above to enable shear thinning to enhanceprocessing attributes of the material. One such additive component ofthe present invention includes a filler. Typically, fillers are added toepoxy foam formulations to lower cost, alter color, reduce reactionexotherm, and control shrinkage rates. Fillers in the form of fineparticles (for example, carbon black or fumed silica) may also serve asnucleating agents. Small particles provide sites for heterogeneousnucleation, which allow for initiation and subsequent growth of foamcells when certain blowing agent types are used. In heterogeneousnucleation, gas molecules driven by supersaturation preferentially formnucleation sites on the solid/fluid interfaces of the nucleating agent.The ultimate cell size is determined by other factors including theexotherm, the rate of cure, the amount of blowing agent, andinteractions between the epoxy and other formulation components.Although a number of suitable fillers are known in the art and discussedin commonly-assigned U.S. Pat. No. 5,648,401, incorporated by reference,a particular preferred additive of the present invention is athixotropic additive formulated within either or potentially both of thefirst and second components which causes both components to beshear-thinning. An example of such a thixotropic filler is an aramidpulp and is sold under the trade name Kevlar 1F543. In a particularlypreferred embodiment, the thixoptropic filler is formulated in at leastone, and potentially both the first or epoxy component and the second oramine component. This additive effectuates shear thinning or anincreased viscosity at a zero shear rate and a decreased viscosity at ahigher shear rate.

[0021] Still further, a number of other additives can be utilized in thepresent invention such as carbon black, solid rubber particles, hollowmicrospheres, and inert polymer particles, if desired in a particularapplication. For example, hollow glass microspheres may be added toreduce the density of the foam while maintaining good strength andstiffness. Commercially available hollow glass microspheres (sometimesalso referred to as glass microballoons or microbubbles) includematerials sold by Minnesota Mining & Manufacturing under the trademarkSCOTCHLITE, with suitable grades including those available under thedesignations B38, C15, K20, and VS 5500. The glass microspherespreferably have diameters in the range of from about 5 to 200micrometers. The crush strength of the hollow glass microspheres may beselected in accordance with the desired characteristics of the curedthermoset foam or chosen reinforced structural member containing suchfoam. Suitable reinforcements may be included as well. For instance,glass fiber is one type of reinforcement since it helps increase thestrength and stiffness of the standard reinforcement foam. The glassfiber may be chopped, milled, or in other suitable physical form.

[0022] Other types of fillers or reinforcements may also optionally bepresent in the foamable composition. Any of the conventional organic orinorganic fillers known in the thermosettable resin art may be usedincluding, for example, silica (including fumed or pyrogenic silica,which may also function as a thixotropic or rheological control agent),calcium carbonate (including coated and/or precipitated calciumcarbonate, which may also act as a thixotropic or rheological controlagent, especially when it is in the form of fine particles), fibersother than glass fibers (e.g., wollastinite fibers, carbon fibers,ceramic fibers, aramid fibers), alumina, clays, sand, metals (e.g.aluminum powder), microspheres other than glass microspheres such asceramic microspheres, thermoplastic resin microspheres, thermoset reinmicrospheres, and carbon microspheres (all of which may be solid orhollow, expanded or expandable) and the like.

[0023] Other optional additives or components which could be utilized inalternative embodiments or formulations of the present invention includediluents (reactive or non-reactive) such as glycidyl ethers, glycidylesters, acrylics, solvents and plasticizers, toughening or flexibilizingagents (e.g., aliphatic diepoxides, polyaminoamides, liquid polysulfidepolymers, rubbers including liquid nitrile rubbers such asbutadiene-acrylonitile copolymers, which may be functionalized withcarboxyl groups, amine groups or the like), coupling agents/wettingagents/adhesion promoters (e.g., silanes), colorants (e.g., dyes andpigments such as carbon black), stabilizers (e.g., antioxidants, UVstabilizers) and the like. In this regard, the preferred formulation setforth below may utilize these additional components such as an optionalcoloring agent, reinforcements and fillers.

[0024] Although the components of the present invention may beformulated in a variety of ranges as disclosed herein, the followingtable sets forth a preferred formulation in percent by weight for thecomponents of the composition of the present invention: (weight %) FirstComponent (Epoxy) DER 331 97.943 Kevlar 1F543 0.748 Expancel 820-DU0.935 Phtalo Green 0.374 Second Component (Amine) Ancamine 2556 60.714GVI 4040 12.500 Kevlar 1F543 1.786 Polyfil 90 12.500 Nanomer I.30.E12.500

[0025] In the method of the present invention, the first or resincomponent and the second or amine component are combined, preferably inliquid form. For example, the materials can be mixed either staticallyor dynamically with the mixture then being placed in a mold cavity ofchosen shape and dimension, the mold cavity can be an automotive bodycavity or any cavity that could be structurally reinforced by thefoam-in-place structural material. In an alternative embodiment ormethodology, atomized streams of the separate components or materialscan be impinged into a mold cavity. The thixotropic filler and the resinare preferably premixed. Once mixed, the composition cures at roomtemperature (that is, without adding external heat).

[0026] It is contemplated that the method, apparatus, and formulationcomprising the present invention is suitable for application, and may beused in conjunction with, a variety of substrates and members used forreinforcement of automotive and aerospace vehicles. Most notably, thepresent invention may be applied, coated, or otherwise disposed uponsubstrates found within portions of an automotive vehicle such assurfaces or members encompassing on automotive rockers, rail members,frame members, cross-members, chassis engine cradles, roof systems,vehicle window frames, vehicle deck lids, lift gates, roof bows, liftgates, roof headers, roof rails, fender assemblies, pillar assemblies,door assemblies, radiator/rad supports, bumpers, a rail member, a framemember, a door assembly, a rocker, a frame cross member, a vehiclewindow frame, a vehicle deck lid, a lift gate, a vehicle pillarassembly, a vehicle hatch, a vehicle roof system, a roof bow, a roofrail, a roof header, a fender assembly, a bumper, and a front endstructure, body panels such as hoods, trunks, hatches, cargo doors,front end structures, and door impact bars in automotive vehicles aswell as other portions of an automotive vehicle which may be adjacent tothe exterior of the vehicle. The targeted placement of the presentinvention within an automotive vehicle will be dictated by performancerequirements and economics of the specific application and requirements.In addition, the present invention may be utilized in conjunction with astructural reinforcement system such as those disclosed in U.S. Pat.Nos. 4,922,596, 4,978,562, 5,124,186, and 5,884,960 and commonly owned,co-pending U.S. application Ser. Nos. 09/502,686 filed Feb. 11, 2000,09/524,961 filed Mar. 14, 2000, 60/223,667 filed Aug. 7, 2000,60/225,126 filed Aug. 14, 2000, 09/676,443 filed Sep. 29, 2000,09/676,335 filed Sep. 29, 2000, 09/676,725 filed Sep. 29, 2000, andparticularly, 09/459,756 filed Dec. 10, 1999, all of which are expresslyincorporated by reference.

[0027] Thus, it is apparent that there has been provided in accordancewith the invention a method and apparatus that fully satisfy theobjects, aims and advantages set forth above. While the invention hasbeen described in connection with specific embodiments thereof it isevident that many alternatives, modifications, and variations will beapparent to those skilled in the art in light of the foregoingdescription. Accordingly, it is intended to embrace all suchalternatives, modifications and variations that fall within the spiritand broad scope of the appended claims.

What is claimed is:
 1. A method for producing a foamed article,comprising the steps of: providing an epoxy formulation, said epoxyformulation comprising an epoxy resin, a blowing agent having athermoplastic shell filled with a solvent core, and a thixotropicfiller; providing an amine formulation, said amine formulationcomprising an amine and a thixotropic filler; and combining said epoxyformulation and said amine formulation to form a reactive mixture andallowing said thermoplastic shell filled with a solvent core to softenfrom amine-epoxy exotherm and then expand due to gas pressure from saidsolvent core.
 2. The method for producing a foamed article recited inclaim 1, wherein said epoxy resin comprises from about 35% to about 99%by weight of said reactive mixture.
 3. The method for producing a foamedarticle recited in claim 1, wherein said epoxy resin and saidthixotropic filler are combined prior to adding said blowing agent. 4.The method for producing a foamed article recited in claim 3, furtherincluding the step of combining said blowing agent with an inert fillerprior to combining said blowing agent with said epoxy resin and saidthixotropic filler.
 5. The method for producing a foamed article recitedin claim 1, wherein said reactive mixture further includes an additiveselected from the group consisting of carbon black, ceramicmicrospheres, polymer particles, rubber particles, ceramic particles,inert mineral particles and combinations thereof.
 6. The method ofproducing a foamed article recited in claim 1, wherein said reactivemixture is adapted for application upon portions of an automotivevehicle selected from the group consisting of a rail member, a framemember, a door assembly, a rocker, and a frame cross member.
 7. Themethod of producing a foamed article recited in claim 1, wherein saidreactive mixture is adapted for application upon portions of anautomotive vehicle selected from the group consisting of a vehiclewindow frame, a vehicle deck lid, a lift gate, a vehicle pillarassembly, and a vehicle hatch.
 8. The method of producing a foamedarticle recited in claim 1, wherein said reactive mixture is adapted forapplication upon portions of an automotive vehicle selected from thegroup consisting of a vehicle roof system, a roof bow, a roof rail, anda roof header.
 9. The method of producing a foamed article recited inclaim 1, wherein said reactive mixture is adapted for application uponportions of an automotive vehicle selected from the group consisting ofa fender assembly, a bumper, and a front end structure.
 10. A method forproducing a foamed article, comprising the steps of: providing an epoxyresin; providing a thixotropic filler; providing a blowing agent havinga thermoplastic shell filled with a solvent core; providing an amineformulation, said amine formulation comprising an amine and athixotropic filler; and combining said epoxy formulation and said amineformulation to form a reactive mixture and allowing said thermoplasticshell filled with a solvent core to soften from amine-epoxy exotherm andthen expand due to gas pressure from said solvent core.
 11. The methodfor producing a foamed article recited in claim 10, wherein said epoxyresin comprises from about 35% to about 99% by weight of said reactivemixture.
 12. The method for producing a foamed article recited in claim10, wherein said epoxy resin and said thixotropic filler are combinedprior to adding said blowing agent.
 13. The method for producing afoamed article recited in claim 10, further including the step ofcombining said blowing agent with an inert filler prior to combiningsaid blowing agent with said epoxy resin and said thixotropic filler.14. The method for producing a foamed article recited in claim 10,wherein said reactive mixture further includes an additive selected formthe group consisting of carbon black, ceramic microspheres, polymerparticles, rubber particles, ceramic particles, inert mineral particlesand combinations thereof.
 15. The method for producing a foamed articlerecited in claim 10, further comprising the steps of placing thereactive mixture in the cavity of an automotive vehicle.
 16. The methodof producing a foamed article recited in claim 10, wherein said reactivemixture is adapted for application upon portions of an automotivevehicle selected from the group consisting of a rail member, a framemember, a door assembly, a rocker, and a frame cross member.
 17. Themethod of producing a foamed article recited in claim 10, wherein saidreactive mixture is adapted for application upon portions of anautomotive vehicle selected from the group consisting of a vehiclewindow frame, a vehicle deck lid, a lift gate, a vehicle pillarassembly, and a vehicle hatch.
 18. The method of producing a foamedarticle recited in claim 10, wherein said reactive mixture is adaptedfor application upon portions of an automotive vehicle selected from thegroup consisting of a vehicle roof system, a roof bow, a roof rail, anda roof header.
 19. The method of producing a foamed article recited inclaim 10, wherein said reactive mixture is adapted for application uponportions of an automotive vehicle selected from the group consisting ofa fender assembly, a bumper, and a front end structure.